A diagram of an EKV. (DoD.)
During the test, a target ICBM missile was launched from the Kwajalein Atoll in the Pacific Ocean and sent out of the atmosphere. At the same time, a sea-based X-band radar picked up the trajectory of the missile and fed coordinates to Vandenberg Air Force Base in California, where two Exoatmospheric Kill Vehicles (EKV) were launched to intercept. Some minutes later, the first EKV intercepted the dummy missile and destroyed it, and the second missile collected data on the intercept test.
While this recent test does demonstrate how a “two-shot salvo” could be effective in intercepting an incoming missile attack, the test did not demonstrate the full potential of such a tactic.
In a true two-shot salvo, both EKVs would begin their mission targeting a potential threat. If the first EKV succeeded in destroying the target, the second EKV would redirect itself to intercept any collateral debris created by the first hit. In the case of a first EKV miss, the second missile would attempt to knock a target ICBM out.
While this test does represent further maturation of the U.S. Missile Defense Agency’s capabilities to intercept ICBMs, it doesn’t prove that a two-shot salvo would be capable of intercepting a missile armed with sophisticated countermeasures meant to fool intercepting rockets. In such a case, two-shot salvos may have to be complemented with further missiles to counteract any chaff and disable the intended target.
As you can imagine, the increase in the number of interceptors increases the complexity of an intercept mission, and likely would just be further counteracted by additional countermeasures—escalation after escalation.
To be sure, missile defense systems are a reasonable deterrent to ICBM strikes, but they represent an action that would only occur if diplomacy between two or more nations had completely shattered. That’s a bad place to be.
Hopefully, diplomacy will continue to be the only salvo required to prevent a nuclear strike.